An international liaison of radiation oncology cooperative groups is proposed to formalize a more active federation world wide of those organizations doing clinical trials in order to achieve: 1) better communications of active trials; 2) better quality assurance of radiation treatment; 3) better description of criteria for entry of patients on study (staging, diagnostic work-up, and end results reporting including late effects criteria); and 4) better leads to selected intergroup studies with either common arms (fractionation protocols) or joint protocols to accelerate patient accrual. The present proposal will permit the formal organization of an international cooperative group to achieve these aims and objectives. A conference, whose participants will represent the leadership of three major cooperative groups in Europe and the United States, will be scheduled for April, 1986, in Paris, France. Through a series of workshops and writing sessions, the conference participants will develop a research plan patterned after the one currently in effect for the Radiation Therapy Oncology Group (RTOG). They will address the priorities in protocol design as well as protocol design itself with regard to modalities and major disease sites. Of special interest will be the modalities that are providing investigations at the leading edge of cancer research such as chemical modifiers, fractionation and time/dose studies, high LET, large field studies (hemi-body irradiation), hyperthermia, isotopic immunotherapy, intraoperative procedures, and brachytherapy. The resulting research plan will provide the necessary coordination and cooperation between international cooperative groups. Upon its completion it will receive the endorsement of the conference participants prior to its debut at national meetings. This will ensure that studies evolve in a meaningful fashion. Publication of this plan will eventually be by a scientific journal such as the International Journal of Radiation Oncology, Biology and Physics. Through development of this comprehensive research plan for international trials, it is anticipated that the scientific methodology of conducting clinical trials will be extended to third world countries to utilize their unique patient resources with a high incidence of specific cancers.